Method and system for transmitting pictures to a distance



Aug. 5 1924.

E. KEEN METHOD AND SYSTEM FOR TRANSMITTING PICTURES T0 A DISTANCE 5 Sheets-Shet l Filed June 13 1922 Aug. 5 1924.

E. KEEN METHOD AND SYSTEM FOR TRNSMITTING PICTURES TO A DISTANCE Filed June 15, 1922 5 Sheets-Sheet 2 Aug. 5 1924. 1,503,590

E. KEEN METHOD AND SYSTEM FOR TRANSMITTING PICTURES TO A DISTANCE Filed June 13, 1922 5 Sheets-SheeiI 5 Aug.A 5 1924. 1 1,503,590

E. KEEN METHOD AND SYSTEM FOR TRANSMITTING PICTURES TO A DISTANCE Filed June 13, 1922 5 Sheets-Sheet 4 l 160 llLq' III.

l Ill' "ll'll muantoz E. KEEN METHOD AND SYSTEM FOR TRANSMITTING PICTURES TO A DISTANCE Filed June 13, 1922 5 Sheets-Sheet 5 Patented Aug. 5, 1924.

UNITED STATES PATENT oFFicE.

ELIOT KEEN, OF NEW YORK, N. Y., ASSIGNOR T0 PICTURADIO CORPORATION, A COB- PORATION 0F NEW YORK.

METHOD AND SYSTEM FOR TRANSMITTING PICTURES TO A DISTANCE.

Application led June 13, 1922. Serial No. 567,936.

To all whom t may concer/n.'

Be it known -that I, Emo'r KniiN, a citizen of the United States, residing in the borough of Manhattan, city, county, and State of New York, have invented certain new and useful Improvements in Methods andSystems for Transmittinc Pictures to a Distance, of which the following is a specification, reference being had to the accompanyin drawings, forming a part'thereof.

y invention relates to a method and system for transmitting pictures to a distance.

The object of the pi'esent invention is to produce a system of this character in which pictures may be rapidly transmitted and in which the transmission is accomplished through the agency of wireless signals.

In its preferred embodiment and most im`- portant aspects, the invention is practiced in substantially the following manner:

The picture to be transmitted is first copied or photographed on a zinc or other suitable plate on which either the dark or the light portions of the picture are distinguished from the rest by the occurrence of closely and evenly spaced corrugations, in relief or sunken, as may bc most convenient. This plate maybe prepared in accordance with any one of a number of lithographie or photographie or etching or engraving methods well known in the respective arts. The processes used in preparing so-called half tone platesjare almost directly applicable. Thus, preferably, the picture is photographically copied through a screen or several screens, whereby the picture is finally reproduced on a zinc plate or the equivalent, being also divided into a plurality of bands, and whereby again within each band the. varying degrees of light, or shade arc represented by groups of closely spaced corrugation lines (raised or sunken, as convenient) the number of lines per group representing the intensity of light or shade.

' This will give in the last analysis a picture composed entirely of fine sunken (or raised) parallel lines, all of substantially the same width and spacing, but varying in length and grouping. 'This form, the preferred one,

but which may be infinitely varied without departing from the spirit of this invention, leaves the final plate used for transmission a mere series of fine corrugations on even centers and of varying length. The bands referred to have in this embodiment no final tangible existence as such, being merely successive grou s of lines or of spaces where lines might. e. Thus, in dark areas of the picture, assuming numerical oupings as shown on the drawings, a band" would comprise seven fine lines; in areas a little less I dark, five, centrally located; in gray areas, three; in light areas, one fine line; and in white areas, no lines atall.

It will be clear that the choice of the above numbers is arbitrary, as is also the direction of the lines. They might be laid across the bands, or diagonally. The concept of bands may be entirely omitted and the picture reproduced in ne parallel lines subject to no arbitrary grouping. Or fine squares may replace the fine lines, or an endless number of variations well known in the half tone and allied arts may be used without departing from the spirit of my invention.

For .fulfilling the purposes of my invention, any plate having corrugations as fine lines or areas on regular centers, whether in relief or slinken, will be suitable except that the corrugations transmit best when all are of equal value. In other words, by the means disclosed orby any other means in accordance with the spirit of this invention` it is not as easy to transmit individual values of individual corrugations as values of groups of similar corrugations. The groups need not, as pointed out, be regular. This statement is only relatively true. Individual values can be transmitted. These state ments will become clear in the light of the further means employed.

In accordance with the preferred embodiment of my invention, the transmitting plate or record is crossed at right angles to the corrugations or lines by the stylus of a phonoprapliic reproducer and will cause 'the production of sounds. The corrugations in a group are preferably close enough to each other to cause the vibration of the diaphragm of this reproducer andthe generation of an audible sound. As the reproducer successively co-operates with the various groups or bands, preferably by causing the record or plate to rotate on a drum under the reproducer, sounds all of a definite pitch willy other bv a silent period, black interspersed with white is being sent, and the light or shade value depends upon the relative length of sound and silent period. The p1tch of all sounds is preferably the same. The depth and width of individual corrugations afiects the intensity of the sound somewhat, and 1t will be clear later, from a consideratlon of the reproducing means, that tlns affords a means of varying somewhat the light of shade of the received picture, i. e., of. transmitting some individual value of indivldual corrugations.

This reproducer is associated with a system throughwhich electric waves, preferablv of aud-io frequency, may be transmitted. Either the usual line wire telephone system or a radio telegraph or telephone transmission system may be used for thls purpose. The latter alone will be discussed.

To any one sklled in the art it will be obvious what modifications ot apparatus would be required for transmisslon by wires.

The vibrations of the phonograph reproducer diaphragm are used for modulatmg the frequency of the radio carrier waves, either by means of the actual sound waves caught in a separate telephone transmitter or by means of a telephone transmitter forming part of the reproducer. Father method results in modulating the contlnuous or carrier wave, whose len th may be as required by the accidents o sending station, commercial conditions, etc., by trains of audio waves, all audio waves being of the same length. To some extent, as pointed out, the individual waves of these trains ma vary in amplitude, i. e., in strength, an the number of waves in a train, and the length of the trains will vary constantly according to the picture beingI transmitted.

It will be obvious to those skilledin the art that instead of thus differentiating between the black and white parts of a picture, the system may be modified-without departing from the spirit of my invention by transmitting signals in which a certain pitch represents the black and a certain other pitch rather than silence represents the white parts of the picture.

All the above described apparatus is at the sending station. The receiving station comprises in addition to the usual equipment for line telephone or wireless telephone receiving stations, a device responsive to the modulated current impulses generated at the transmitting station. This responsive device comprises a sensitive element vibrated by the audio waves in front of an aperture through which a beam of light may betransmitted to a light-sensitive film. While vibrating, this element does not visibly obstruct the passage of the light ray. `When,y however, the element is not vibrated by audio modulations of the carrier wave, it comes instantly to rest temporarily, obstructing the passage of the light ray through the aperture. A light sensitive film rotates within a chamber, and back of said aperture, at a speed corresponding to that of the plate or picture at the sending station. Both the sending plate and the receiving film are traversed longitudinally while rotating after the manner of a phonograph cylinder. The result will be the printin dark fines corresponding to corrugated areas of the plate at the sending station.

In order to insure synchronism between the sending and receivin stations, suitable stop and start, or ot 1er synchronizing means must be provided. Any of the well known synchronizing means used in printing telegraphy may be adapted for the purose.

The drawings represent a preferred embodiment of my invention. Fig. 1 is an elevation, partly in section of the sending cylinder and reproducer'; Fig. 2 is a sectional view of the same cylinder and phonographic reproducer, showing also a telephone transmitter; Fig. 3 is an enlarged detail view of a portion of the developed surface ot the sending plate; Fig. 3a shows a negativerom which the plate of Fig. 3 is prepared; Fig. 4 shows the receiving galvanometer and an end view of the receiving cylinder; Fig. 5 is an elevation of the receiving cylinder together with a sectional view of the driving control; Fig. 6 shows the sending circuit with a sectional view of the microphonic reproducer; Fig. 7 shows the' receiving circuit; and Fig. 8 shows a modied receiving circuit.

The sending apparatus is mounted on a table l and consists of a sending record or plate 2 which is held around ya cylinder 3 by a suitable clamping means such as rings 4. The cylinder 3 is fixed to a horizontal shaft 5. One end of the shaft 5 passes through a pulley wheel 6 rotatably mounted in suitable earings 7. The pulley 6- is keyed to the shaft 5 with a long key-way 6* whereby the shaft may be horlzontally displaced. One end of shaft 5 is screw-threaded at 8 and cooperates with a stationary sup ort and halfnut 9 in such a manner that, 1n response to each com lete revolution of the shaft 5, the shaft an the cylinder 3 will be displaced bi1 one step in a right-hand direction ig. 1).

A -sound reproducing device 10 is carried on the table 1 at 11 in such a manner that its stylus l2 cooperates with the plate 2 and passes across this plate at intervals determined by the lead of the thread 8. A lever 3 (Fi 2) carrying the stylus is pivoted at 14 to t e relativelyheavy floating plate 15 pivoted on the fixed casing 16. The stylus 12 is carried at one end of this lever 13, the other end of the lever being connected with by the ray on the sensitized film of one end of a link 17. Link 17 protrudes through an aperture 18 in the plate 15, and

its other end is fixedat 19 to a dia hragm` 20 clamped in the casing 16. T e dlaphragm 20 is Surrounded by a horn21, and

the sound vibrat-ions produced thereby may actuate a telephone transmitter 22.

The reproducer diaphragm 20 is vibrated b v means of the plate 2 which acts as a phonographic cylinder record of the hill and valley type. The hills on this record are indicated by the blacklines andthe valleys by the white spaces, or vice versa. It Fig. 1 of the drawings isvturned around so that the screw-threzuled end 8.0i shaft 5 points towards the reader,it will be seen that the 'picture obtained by the black and white combination represents the proiile of a man. the representation being composed of black lines 30 of varying widths. Obviously, it is a matter of convenience or choice whether the picture is defined by black lines on white, or vice versa.

Referring now to Fig. 3, it will be seen that cach one of the heavy black lines 30, which were referred to as bands, is actually composed oi a plurality of black lines representing the corrugations above referred to.

The picture to be reproduced is first enlarged on a film or transparent plate, is then printed through a relatively 4coarse screen `or grating having substantially equal open barred stripes, and held at some distance from the sensitized film. The object is to convert the varying degrees of light of the original enlarged film into stripes of developed emulsion of varying widths. Fig. 3

shows, much enlarged, a minute part of al film thus obtained. This is according to principles ofthe well-known half-tone process, except that the screen is a one-way screen and not divided into squares. The .film illustratedin Fig. 3EL .is printed preferably on a sensitized zinc plate through a second one-way screen seven times as fine as the first, and with'the film and screen held close to the plate. The object is to convert the white areas of Fig. 3 intoareas of closely spaced lines 30a, as illustrated on Fig. 3. Tt will be observed that 'Figs 3 and 3, though of different appearance, actually define the same outline andv light values.

The developed 'zinc plate is preferably coated with dragons blood, or by other chemical means so treated that a slight difference oi level is obtained between the light struck areas and the others. This results in a. plate suitable to eo-operate with a phonographic reproducer.

The top edge of the zinc plate (Fig. 3) i provided by chemical or mechanical means with a band of corrugations 31 more widely spaced than the corrugations 30. The'lovwer edge of theplate is leftblank for a suitable margin 31".

Instead of the usual sound producing phonographic reproducer 10, a microphonie reproducer of any suitable type such as the one shown in Flg. 6 may be provided to respond to the vibrations of the stylus 12 when actuated by the corrugations of the surface of plate 2. In this ease, the lever 13 and rod 17 are actuated by the stylus 12 to transmit the vibrations to a telephone transmitter diaphragm 40 clamped in the casing 16.. The dlaphragm 40 carries a transmitter button composed of front and rear electrodes 41 and 42 and a carbon granule chamber 43. The electrodes and carbon granule chamber are included in a circuit comprising also conductors 44. The resistance of this circuit is varied in the well known manner in response to the compression and dilation of the carbon granule chamber 43.

The apparatus at the receiving station is illustrated in Figs. 4, 5 and 7. This apparatus -is mounted on a table 100 and comprises a film chamber 101, a string galvanometer 102, and a source of light 103. The galvanometer field is maintained by a suitable local current supply through the agency of coils 104. The pole pieces'105, 106 are perforated at 107, 108. A conducting string 109 is stretched between the two pole pieces. The beam of light passing through the perforations 107, 108, is suitably restricted by a small diaphragm 110 having a minute aperture. While the string 109 is vibrating, the light rays coming from source 103 are not visibly impeded. These light rays are focused to pass in parallel lines through perforation 107 by means of convex and concave llenses 111, 112 suitably positioned in a holder 113.- When leaving perforation 108, the light rays are again focused b'y means of a convex lens 114 to pass through an opening 115 in the side wall of chamber 101 and strike against a roll of light-sensitive film 116 fastened to a cylinder 117 b means of hoops 118. Depending on the ciaracteristics of the wave trains traversing the string 109, the periods of its vibration and rest will be varied and to some extent its amplitude. During the periods of rest, the string will prevent the. passage. of' light through diaphragm 110 since the opening therein, which is preferably a longitudinal slit parallel with the string, is completely Covered by the string at rest. lt will be obvious from the above that, the greater the amplitude of the string vibration, the more rapidly the string will pass over the slit, and that thus the amount of light admitted in a given time can be somewhat varied by the strength of the received Waves. As stated above, this furnishes mea-ns where- .by individual values (depth of etching, etc.)- of the fine corrugations on the sending plate can be reproduced on the received picture.

The cylinder 117 carrying the lightsensitive film is mounted within the easing 101 on a horizontal shaft 120 supported in suitable bearings on the table 101). The

chamber 101 .is provided with wheels 121 1 long to permit the horizontal displacement of the shaft 120 4and cylinder 11 7. The clutch 127 is normally held in frlctional envgagement with the driving wheel 125 by means of a coiled spring 130. An electro- 1 magnet 131 fastened to the table 100 may be operated to withdraw and grip the clutch 127 from engagement with the wheel 125 against the action of the spring 130 for arresting the rotation of the shaft 120.

`Keyed to the shaft 120 with the long keyway 1.29 are interrupters 132, 132, 132b and cam 133. By means of their conducting segments 134, 1311a and 134", the interrupters 132, 132a and 132b control the closing of circuits terminating in wipers 135, 135a and 135", and by means of a projection 136, the cam 133 may cause the closure of a circuit including contact springs 137 which normally tend to separate.

One end of the shaft 120 is screw-threaded at 140 and co-operates with a half-nut 139 in such a manner that, in response to one complete revolution of the shaft it will cause the horizontal displacelnent by one step. The cylinder 117 is preferably smaller than the cylinder 3, because for mechanical reasons the corrugated sending plate 2 is largerthan the umially required size of the received picture.

In order to insure the proper time relation between the rotations of cylinders 3 and 117, which time relation must be very accurately maintained if the received picture is not to be distorted, means to produce synchronous or isochronous revolution of the two cylinders must be provided. Any such system well known in printing vtelegraphy and the allied arts may be readily adapted for the purpose. In the present embodiment, a form of the so-calledstop-start system is disclosed. This comprises means related to the sending cylinder to generate a starting pulse or tone, preferably distinguishable from other pulses r tones; means to transmit this pulse to the receiving station, which in thel present Icase are identical with the transmitting means for the picture-identifying pulses; control means at the receiving station, operated by the starting pulse, to set in motion the receiving lgizing coils 151.

cylinder; and means to bring the receiving cylinder to rest after one revolution always in the same position. 4

The starting pulse or tone is generated by the corrugations 31 on the plate 2, which, being on different (larger) spacing from the corrugations 30, generate a wave train ot' dicrent (lower) frequency from the picture wave trains.

The control means shown in Fig. 7 comprises a permanent magnet 150 provided with sott iron pole pieces carrying enerl Opposite the le pieces ot the magnet 150, an iron diapliiiagm 152 is loosely supported on three rest points 152, preferably located on the nodal ring of the diaphragm. The diaphragm must have such diameter and thickness as to have a fundamental period like that of the starting wave-train. A Contact 152 pivoted on a fixed support 154: rests with its own weight on a contact point 153a in the center of the diaphragm. These contacts control a circuit comprising a resistance 155, a marginal relay 156 and a source of electrical current 157. The contacts of relay 156 controla circuit comprising the cam contacts 137, a source of electrical current 158 and the clutch magnet 131.

The operation of the system in transmittinga picture is as follows:

Let us assume that the receiving station is in its normal position of rest, and that the sending cylinder 3 is rotating in the direction of the arrow (Figs. 2 and 3).

The first result of the motion of the sending cylinder is that the stylus encounters the, corrugations 31. )Vhile riding over corrugations 31,-the carbon button 43 is subjected to a vibratory pressure and produces a train of waves corresponding to corrugations 31 which' will be referred to as the starting note.

As shown in Fig. 6, this train of waves is used to modulate the carrier wave of a continuous wave transmitting system. The electrical and mechanical means used for these purposes form no part of the present invention, which is applicable to any known or possible radio telephone system. Fig. 6 shows a simple ystandard circuit that may be used, and a further explanation of which will be dispensed with.

The starting note on its carrier wave is received on a. receiving antenna circuit (Filg. 7)

asses through a radio frequency amp ifier, 1s rectified in a detector circuit, and then passes through, if desired and as shown` an audio frequency amplifier from which it is repeated as an alternating current wave train by the audio transformer secondary '160, in a circuit comprising conductor 161,

brushes 135, `conducting segment 134 on which the brushes are resting, conductor 162, magnet coils 151, conductor 163, and

' back to transformer secondary 160. The

speed of the sending cylinder is such tha-t the pitclrof the starting note is the fundamental of diaphragm 152. The starting.

note, therefore, sets the latter into vibration. At this time relay 156 is energized through the following circuit: battery 157, diaphragm 152, contacts 153, contact niemer. ,153, support member 154, high resistance 1,55, the winding of relay 156, and back to battery 157'. The value of resistance 155 is such that the relay is very weakly magnetized. The vibration of diay phragm 152 will .break this circuit, whereupon relay' 156 instantly drops its armature and opens the energizing circuit of clutch magnet 131 which until now has-been energized. The de-energiza-tion' of this magnet (Fig. 5) releases the clutch 127 which engages pulley-wheel 125 and sets shaft 120 and cylinder 117 interrupters `132, 132, 132 and cam 133 in motion. f-

c At the sending station the stylus next encountersy the corrugations a and, as described in the case of corrugations 31, wave trains of a somewhat higher frequency and lengths, as determined bythe sending plate,

- are generated -and received. vBy 'this time,

kses

due to the rotation of Vshaft 120, the interrupters are in such position that the circuit from transformer secondary 160 through conductor 161 is no longer closed through wipers 135, butthrough wipers 135, segment 134, conductor 164, resistance 165, string'109, conductor 163, and back to transformer secondary 160. String 109 responds to the wave trains and light is admitted to the film 116on the receiving cylinder 117 in quantity and duration as determined by the strength and length of the wave trains. Light is prevented access to the film for times corresponding to the passage of the sending stylus over blankN areas of plate 2.

The speed of the motors driving the sending and receiving cylinders must noty vary materially or the received picture will be distorted. Clearly, the speed of the receiving cylinder. is slightly higher than that of the sending cylinder for the latter rotates continuously, whereas the receiving cylinder starts from rest, rotates during the transmission of picture wave trains, stops and awaits ,the starting note, repeating this cycle for every revolution of the sending cylinder. The stopping of the receiving cylinder occurs as follows:

After the stylus has traversed all corrugations 30* andhas entered upon blank margin 31EL of plate 2, at the receiving station, conducting segment 134 makes contact with brushes 135. A circuit is now closed from l battery 157, winding of relay 156, brushes time the circuitof magnet 131 is open at contacts 137. As interrupter 132 revolves further, left-,hand wiper 135 breaks contact with segment 134 and opens-the shortcircuit thereby originally aHorded around resistance 155.. Relay 156 remains up, being f eebly energized through the above traced circuity including diaphragm 152 which by this time has come to rest. In this connectlon, it should be noted that diaphragm 152 has not been responding to the picture transmlttlng Wave trains which are of higher frequency than its fundamental.

Clutch magnet 131 remains de-energized and shaft 120 continues to rotate until cam 133 closes the contact 137 by its point 136, thereby completing-the circuit from battery through contacts 137, front contact and armature of relay 156, clutch magnet 131, and back to battery. Clutch'magnet 131 withtdraws clutch member 127 from pulley 125 and grips it, stopping it instantly.

Thls cycle of operations is repeated for every revolution of the sending plate until the whole picture is transmitted. The sendj ing and receiving cylinders having been horizontally displaced b their lscrew-thread, are reset by hand be ore sending any further pictures. t

The film 116 must, of course, be developed and fixed like any other photograph.

Fig. 8 shows a modified form of synchronizing system. If this system is used instead of the one shown in Fig. 7, the circuit leading to the string 109 includes only resistance 165 and the transformer secondary 160. The receiving circuit used is identical with that shown in Fig. 7 as far as the .transformer 160. The transformer used in the lpresent case has two -secondaries 160 and 170.

The transformer secondary 170 is the input of an audio rectifier tuned to the frequency of the starting note by means of condenser 171. The` output of this circuit is pulsating audio frequency current which traverses the left-hand or knockdown winding of relay 156. The relay 156i is feebly energized through its right-hand winding by battery 157 through resistance 155. The pulsating current in the left-hand winding is suflicient to de-energize this relay which opens the circuit of clutch magnet 131 in exactly the same manner as explained in connection with Fig. 7. The reenergization of the relay is controlled by interrupter 132 in the above-described manner.

As will be understood from the preceding description, the speed limitations are in the in terms of the described picture transmission method may represent a value equivalent to upward of twenty square inches of received picture area per minute.

'liei'e the term audio' frequen is employed herein, it is to be underst as compichendiiig frequencies of super aud ibility; and where the-phrase wave-trains is used,

it is to be understood as comprehending the `biliti s of a train com rised of a single possl L p 'means controlled by the received currents wave.

In the means selected for. illustration fas the preferred form of my invention, I have shown those now believed by me to be best adapted for attaining the stated ob]ects of invention, but such means are themselves susceptible of a wide range of modifisoun cation without departure from the spirit of my disclosure.

I believe my invention, as above described, to be broadly novel, both as to the methods involved and the ran e of possible physical embodiments thereo Since the physical means of practice of my method are capable of expression in a great variety of structural forms, I do not intend to be understood as limiting the scope of m disclosure by any particular description t ereof contained in the specification.

What I claim is:

1. The method of picture transmission consisting in preparing a plate on which every area, graduation and outlineof a picture is represented by corrugations and blank spaces, producing .sound currents representing the corrugations, transmitting the sound currents, receiving the sound currents, and finally converting the sound currents into light variations.

2. The method lof picture transmission consisting in producing waves of certain characteristics representing predetermined parts of a picture, and waves of .certain other characteristics representing points outside of the picture. A

3. The method of picture transmission consisting in producing waves of certain frequency representing predetermined parts of a picture, and Waves of certain other frequency representing a margin line of the picture.

4. The methods of picture transmission consisting in producing Waves of certain audio frequency representing predetermined parts of a icture, and waves of certain other audio requency representing a margin line of the picture.

5. In a picture transmission system, a plate on which a icture is represented by corrugations and blank spaces, means for producing sound currents representing. the corru ations, means for transmitting the currents, means for reoeivin the sound currents, a light-sensitive m, a source of light, andmeans controlled by the ducin sound currents representing the corrugat1onsmeans for transmitting the sound currents, means for receiving the sound currents, a light-sensitive film, a source of light,

for admitting' light to said film.

7. In a picture transmitting system, an

audio wave producing device variably o erable in accordance with the dark and ligiit portions of a picture, a device responsive to the audio waves, a light-sensitive film associated with the said responsive device, and means controlled by the said res onsive device for varying the amount of lig t that may reach the said film. y

8. In a picture transmission system, a transmitting plate, corrugations thereon to distinguish certain areas of said plate, different corrugations to distinguish certain other areas on said plate, a phonograpliic element operable by 4said corrugations, va. telephonie element responsive to the operation of said hono aphic element, means including said) telep ionic element for generating electrical waves of different frequencies, a device responsive to the waves representing said certain areas of said plate, a movable film of light-sensitive material, a source of light, means controlled by the said resposive device for varying the amount of light admitted -to said lilm, another device responsive to the 'waves re resenting the said certain other areas of sai plate, and means controlled by said other device for controlling the moving of said film.

9. In a picture transmission system, a transmitting plate, corrugations thereon representing t e black parts of the picture, different corrugations thereon representing the margin line of said picture, a phonographic element operable by said corrugations, a telephoiiic element responsive to the operation of said phonovraphic element, means including said teleplionic element for generating electrical Waves of a relatively high frequency when said phonographic element is-actuated by the first-,mentioned corrugations and electrical waves of a relativel grap ic element is actuated by said secondmentioned corrugations, a device responsive tothe hi h frequency waves, a movable film of lig t-sensitive material, a source of light, means controlled by ,said responsive device for varying the amount of light admitted to said film, another device responsive to the low frequency waves, and means controlled by said other device for controlling the moving of said film.

`tively low frequency when said phonographic element isv actuated by said secondmentioned cori'ugat'ions, a device responsive to the high frequency Waves, a movable film of light-sensitive material,-a source of light illuminating said film only when said responsive device is operating, another device responsive'to the low frequency Waves, and means controlled by said other device for controlling the moving of said film.

1l. In a picture transmission system, a transmitting. plate, relatively iine corrugations thereon representing the black parts of the picture, relatively coarse corrugations thereon representing the margin line.

of said picture, a phonographic element operable by said corrugations, a telephonie element responsive to' the operation of said phonographic element, means-including said telephonie element for generating electrical Waves of a relatively high lfrequency when said phonographic element is actuated by the fine corrugatons, and electrical Waves of a relatively low frequency when said phonographic element is' actuated by the coarse corrugations, a device responsive to the high frequency Waves, a movable film of light-sensitive material, a source of light, means controlled by the said responsive device for varying the amount of light admitted to said film, another device responsive to the low frequency Waves', and means controlled by saidother device for controlling the moving of said film.

12. In a picture transmission system, a picture representing medium, indicia thereon to distinguish certain areas thereof, a phonographic element operable by said indicia, a telephonie element responsive to the operation of said phonographic element, means for generating Waves, means for modulating said Waves by the telephonie element, a device responsive to the modulated Waves, a movable film of light-sensitive material, a source of light, means controlled by said responsive device for varying the amount of light admitted tosaid film, means for sending controlling impulses, and means controlled by said controlling ifplnpulses for controlling the moving of said 13. In a picture transmission system, a

transmitting plate, corrugations thereon to distinguish certain areas of' said plate, different corrugatioiisto distinguish certain other-.areas on said plate, a pnonographic element operable by said corrugations, a telephonie element 'responsive to the operation of said phonogralihic element, means for generating electrical waves, meansl 'for mod ulating saidl waves by the telephonie element, a device responsive to the modulated Waves representing said certain areasN yof said plate, a movable film of light-sensitive material` a source of light, mea-ns coning the amount of light admitted to said film, another device responsive to the modulated Waves representing the said certain other areas of said plate, and means controlled by said other device for contro-lling the moving of said film.

14. In a picture transmission system, a. transmitting plate, corrugations thereon to distinguish certain areas of said plate, different corrugations to distinguish certain other areas on said plate, a phonographic element operable by said corrugations, a,

telephonie element responsive to the operation of said phonographic element, means for generating electrical Waves, means for modulating said Waves by the telephonie element. a string galvanometer responsive tov the modulated Waves -representing said cerain areas of said plate, amovable film of light-sensitive material, a source of light, means controlled by said string galvanometer for varying the amount of light admitted to said film, a device tuned to the modulated Waves representing the said certain other areas of said plate, and means controlled by -said device `tor controlling the moving of said film.

15. In a picture transmission system, a transmitting plate, corrugations thereon to distinguish certain areas of said plate, different corrngations to distinguish certain other areas on said plate, a phonographic `trolled by said responsive device for varyloc element operable by said -corrugations, a

telephonie element responsive t0 theoperation of said phonographic element, means for generating electrical waves, means for modulating said waves by the telephonie element. a device responsive to the modui plate prepared from a picture having corrugated and smooth areas to represent dlfferentw light values of the picture, anda corru ated area representing the margin line o the picture.'

17. In a picture transmitting device, a

plate prepared from `a picture having finely and a smooth area representing anotherA margin line of the picture. a

19. The method of making plates for. transmittingl pictures which consists in first copying the picture on a plate by -represent' ing certain areas of the plcture as relatively coarse dark and light lines, and certain other areas as light areas, copyin' the imprint thus obtained on a second plate by representing the light areas as areas of relativelyvv fine llnes, and the dark areas as blank spaces.

F. The method of making plates for transmitting pictures which conslsts in first copying the picture on a plate in the form of relatively wide dark and light bands,

copying the imprint thus obtained on a secphotographing the imprint thus obtainedon a second sensitized plate through a relatively line screenheld close to thel plate.

22.4 The method of making plates for transmitting pictures which consists in first photographing the picture on a sensitized plate through a relatively coarse one-way screen held at a distance from the sensitized plate, photographing the imprint thus obtained on a second sensitized plate through arelatively fine onelway screen held closc to the late.

23. e method of making plates ifor the transmission of pictures 1n which the various li ht values of -the picture are firstrepresente by dark and light lines of various width, and then these lines are subdividedinto dark and light lines.

ELIOT KEEN. 

